Method of producing screen pipe



C. J. COBERLY METHOD OF PRODUCING SCREEN PIPE Dec. 27,1927.

Filed Dec. 29. 1926 [Afr 2710191? Cknmnvc: L/. 5?

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A rrozm z'x .Patented Dec. 27, 1927'.

STATES (ILARENCE Jf. COBERLY, 01 LOS ANGELES,

CALIFORNIA, ASSIGNOB TO KOBE, INCOR- PORATED, OF LOS ANGELES,CALIFORNIA, A CORPORATION OF CALIFORNIA.

METHOD OF PRODUCING SCREEN PIPE.

Application filed December 29, 1926. Serial No. 157,808.

My invention relates to a method of forming narrow slots in a pipe andis particularly useful for making strainer pipe which is used in the oilproducing industry. In the oil producing industry, after the well hasbeen drilled and the water casing set therein, an oil string isinstalled in the well, the lower end of the oil string having a strainerpipe attached thereto. This strainer pipe passes through the oil-bearingsands and has small openings therein through which oil passes to theinterior of the oil string. These perforations in the strainer pipe areintended to be so narrow that only oil may pass into the oil string, thesand and gravel being excluded since they are not small enough to passthrough these perforations. It will be seen that it is quite essentialthat these slots be very narrow in order that fine sand be excluded fromthe well. It is ordinarily considered a difficult job to form extremelynarrow slots in strainer pipe.

It is an object of this invention to provide a method whereby quitenarrow slots may be formed in a pipe with facility.

Other objects an advantages will appear in the following descriptiontaken in connection with the drawing, in which Fig. 1 is a perspectiveview illustrating the first step in the method.

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

Fig. 3 is a diagrammatic view illustrating a second step in the methodof the invention.

Fig. 4 is a perspective view showing the final product of the invention.

Fig. 5 is a section taken on the line 5--5 of F1 4.

Ref erring in detail to the drawing, and particularly to Fig. 1, thenumeral 11 represents an oversize pipe having a very thick wall 12. Thefirst step in the method is to provide the pipe 11 with slots 13. Theslots 13 may be formed by means of a mill cutter as indicated at 14, orthey may be provided by cutting the slots in the pipe, using anoxy-acetylene cutting torch. The slots 13 are considerably wider thanthe desired width of slot for strainer pipe.

Referring to Fig. 3, the next step in the method is to reduce the sizeof the pipe to the proper diameter. In Fig. 3 I illustrate a mandrel 16which is secured to a revolving shaft 17. This mandrel 16 is extendedinto the pipe 11 as shown. Operating against the outside of the pipe 11is a pair of forming rollers 18. The pipe 11 is r0- tated in thedirection indicated by the arrow 20 and the mandrel 16 is rotated in thesame direction. The forming rollers 18 are rotated in directionsindicated by arrows 21.

The operation of the mandrel and rollers, as is obvious from Fig. 3,reduces the diameter of the pipe 11 from that indicated at A in Fig. 3to that indicated at B. The thickness of the wall 12 of the pipe 11 isreduced from the thickness indicated at O to the thickness indicated atI). When the pipe 11 is drawn to size the opposing walls of the slots 13are moved together so that these slots are much narrower than theiroriginal width as indicated in Fi 1.

In Figs. 4 and 5, I ifiustrate the pipe 11 after it has been drawn tosize. It has been reduced in diameter and the thickness of the wall hasalso been reduced. The width of the slots 13 as is obvious is much lessthan before the sizing operation. It should be clearly understood thatthe sizing operation shown in Fig. 3 is purely diagrammatic and isrepresentative of any means for drawing the pipe to size. Other means mabe employed without departing from t e spirit and scope of theinvention.

As previously mentioned it is considered difficult to out very narrowslots in pipe. In my invention it is unnecessary to out very narrowslots. The slots 13 cut in the original oversize pipe 11 can be wideenough so that they may be conveniently cut, whether they be cut by amill cutter, oxy-acetylene torch, or other means. The slots 13 arereduced in width by reducing the diameter of the pipe 11. Incidentallyit is found advisable to also reduce the thickness of the wall, althoughthis is not absolutely necessary. The final product shown in Figs. 4 and5 has very narrow slots which are surprisingly accurate in shape andsize. I have demonstrated that a screen pipe made according to thisinvention is better than the ordinary screen pipe because the slots arenarrow and more accurate and is as economical as the ordinary screenpipe because of the ease with which the original slots 13 may be outsince they are quite wide.

The broad conception of the invention consists of a method for formingslots in pipe which consists of providing a pipe with oversize slots andthen operating upon the in such a manner as to reduce the widt theslots,

I claim as my invention:

1. A method of forming narrow slots in pipe comprising: forming a pipe;forming a slot in said pipe after said pipe has been formed; andreducing the width ofsaid slot by reducing the cross section of saidpipe.

2. A method of forming narrow slots in pipe comprising: forming a pipe;milling a slot in said pipe after said pipe has been formed; andreducing the width of said slot by reducing the cross section of saidpipe and p PP reducing the thickness of the wall of said 3. A method offorming narrow slots in pipe comprising: forming a pipe; mechanicallyforming a slot in said pipe after said pipe has been formed, said slotbeing wider than desired; and reducing the diameter of said pipe, thewalls of said slot being moved together, thus narrowing said slot to thedesired width.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 21st day of December, 1926.

CLARENCE J. COBERLY.

